Arquivo de etiquetas: pilares da descarbonização

The Key Technological Challenges of Deep Decarbonization II

Grid Management of Power Systems with High Penetration of Renewable Energies

Here we’re going to discuss how the challenge of managing power system, so the way we produce electricity; how the challenge of managing power system with high shares, high proportion of intermittent renewable energies can be met.

So by intermittent renewable energies we mean some of the renewable energies that are intrinsically time variable in the way they produce energy such as wind power or solar energy, but I’ll come back to that in a moment. The good news, to start with is that the cost of power generation through renewable energies is declining very sharply as a result of at least two different effects.

  • The first being technological advancements as a result of research and development.
  • The second being the economies of scale as they progressively become more and more deployed in our energy systems.

621The cost of the solar photovoltaic cells in particular has declined very, very sharply in the recent years as you can see on this graph. You can see on the graph that the cost per watt of crystalline silicon photovoltaic cells, so that is the main technology that is being used today to generate electricity out of solar energy, that I’ll discuss in a moment, which other types of technologies potentially even more could be used in the future.

But you already see on that graph a very, very compelling decline in the prices of these cells. I mean they went from $76 U.S. dollars per watt in 1970 to $0.74 in 2013, some…an effect that is sometimes called the Swanson effect and that should, well ring a bell. I mean it really looks like the Moore’s law in the semiconductor industry.

622The cost of the wind turbines has also declined, although a bit more gradually. I mean nothing as spectacular than the cost of the photovoltaic cells, but still a significant decline in the recent years.

It’s important to underline here that the price per watt of solar photovoltaic cells is not the same thing that the price of producing electricity through solar photovoltaic energy which is sometimes called by the energy experts, the levelized cost of energy, LCOE. And in fact the price of producing electricity through solar photovoltaic energy remains more expensive than the alternative sources of electricity production, at least in many places.

It’s not the case everywhere. It’s true that solar photovoltaic energy has reached what we have called in the previous chapter, the grid parity. So the cost at which it is competitive with other sources of power generation. So solar photovoltaic energy has reached this grid parity in several regions and, and countries, but not everywhere and…by far. So their costs still need to significantly further decline to enable eventually their very large-scale deployment at a competitive cost. That being said, and it’s an important point I want to make, going forward, the main challenge in relation to renewable energies is likely to be not their costs but how to operate power system with high penetration of intermittent renewable energy.

623So what is that? I mean what is really the problem and, and how do these renewable energies really differ from the other sources of power generation we have today, like coal or gas or hydro or nuclear? And why does it make the operation of the power system more difficult and more challenging? Well as I said, it’s because solar and wind energy are intrinsically in a way time variable for a very simple reason, it’s because wind is not always blowing and sun is not always shining.

So that’s a defining characteristics of these technologies. But on the other hand, the power grid needs to be able to match energy demand and energy supply on a moment by moment basis to maintain the functionality of the power system to make sure that each and every time you need energy there is an energy source to supply and meet your demand.

Traditionally, this is accomplished by using large generators such as coal-fire power plants, or nuclear power plants to provide what is called base load power. And these stable base load generators are then complemented by flexible, readily dispatchable units of power generations such as gas turbines to make a system overall capable of as I said, matching supply and demand at any point in time by the addition of base load power and flexible, readily dispatchable units of power generation.

B624ut going forward, we need to find new low carbon solutions to the issue of supply and demand balancing because as you can see, we cannot in a world where we try to avoid the dangerous effects of human-induced climate change and therefore in a world where we try to deeply reduce the energy emissions, we cannot rely on coal powered generation and gas turbines to, or at least not without carbon capture and sequestration to ensure the balancing of the energy system and going forward, dealing with the intrinsic time variability of some of the renewable energy.

So how can we do that? How can we ensure power system balancing while meeting the constraint of deep emission reductions? Well there are three main ways in which a power system with high penetration of renewable energies can be balanced while again, meeting this constraint of deep decarbonization.

  • The first one is that the intermittent renewable energies, so again, wind, solar, typical examples, can be complemented with other stable sources of low-carbon power supply such as nuclear power, or coal and gas fired power plants, but with carbon capture and sequestration. That’s very important. Not freely emitting coal and gas. Coal and gas plus CCS, or other example, hydropower for countries that have such a potential. Or we can also build a system that links the uncorrelated or that links negatively correlated sources of intermittent renewable energies because that’s a way of dealing with the intermittency of each type of renewable energy; by making sure that combined, we don’t have or this intermittency or at least that we reduce it. So that was for the first broad category of things we can do to balance the energy and the energy supply and the energy consumption with high penetration of renewable energy.
  • Second, there is also great potential to better adjust the time profile of energy demand to the time profile of power supply. And this is broadly speaking what we call demand management. And the truth is that the cost of demand management technologies have declined very significantly.

So it’s not so much an issue of cost going forward, but the main challenges are going to lie in information management, grid management, but also in setting the appropriate economic incentives for demand management. So this is something really interesting, that has great potential to help operate power system with high share of intermittent renewable energies, but the truth is that it’s not going to be sufficient. What will be absolutely critical is to improve our energy storage options.

That’s really important, energy storage. And there is already a variety of electric storage technologies that are known and have been demonstrated on a broad range of time scale from seasonal to daily to hourly to second by second storage, because we need all of that to ensure the functionality of the power system.

625For example, large-scale pumped hydroelectric storage has been cost effective in many countries for decades, but the problem is that it is not available everywhere.

So it will be very important to develop other storage technology options and there are currently a number of options being considered such as batteries or compressed air or hydrogen, but it’s also clear that further research, development and demonstration is going to be required to determine how best to match diverse storage technology options and their cost effective applications and how to commercialize these technologies at a large scale and at a competitive cos

The Deep Decarbonization of Energy Systems IV

A Global Mitigation Scenario

Welcome to the last chapter of lecture five, Chapter four. In the previous chapter, I introduced the three pillars of the deep decarbonization of our energy system. So let me just very quickly recap what they are.

  • the energy efficiency and conservation measures.
  • the production of low carbon electricity.
  • the fuel switching from high carbon to low carbon energy carriers.

As I said, these three pillars represent the overarching framework for these deep decarbonization strategies of our energy system. But before we conclude this lecture, there are still two questions that we need to answer.

  • The first is how do these pillars apply to the different sectors of the economy and how can the coordinated implementation of these three strategies result in the overall deep Decarbonization of the economy?
  • The second question is very importantly, the quantification of their effect by how much do each sector emissions need to be reduced to reach level of deep decarbonization consistent with the objective of limiting the increase in mean surface temperature below 2-degree Celsius?

To answer these two questions we’re going to use the results of a global modeling scenario. 541The graph in the top left corner represents the business-as-usual scenario, or the continuation of the current trends. This is if you will, the scenario if we don’t implement climate change mitigation policies which by the way, means that this is a scenario in which we don’t avoid dangerous climate change and we would face the catastrophic consequences from an uncontrolled climate change. As you can see on this graph, on the top left corner, CO2 energy emissions are increasing sharply. They go from approximately 35 gigaton of CO2 energy emissions by 2015 to more than 50 gigaton of CO2 energy by 2050. And in this scenario, in this business-as-usual scenario, emissions from all sectors are rising, but in particular, the emissions from power generation.

542To the country the graph in the top right-hand corner represents a 2-degree Celsius scenario. So in, in this scenario the CO2 emissions are reduced over time to a level that is consistent with the objective of staying within 2-degree of global warming. And as you can see on this graph, on the top right-hand corner emissions peak by approximately 2020 and then they’re reduced, they’re in fact reduced dramatically to approximately 11 gigaton of CO2 energy by 2050. So what do we really learn from the results of this global mitigation scenario? Well it shows a few important things.

  1. First it shows that staying within the 2-degree limit requires deep emission reductions in all sectors of the economy. Profound emission reductions in power generation, industry, transport and buildings. But what is interesting is that it shows also that these sectoral emissions, the emissions from the different sectors are reduced in different proportions. And that is due mainly to two factors.
    1. I mean first, the fact that the different sectors do not have the same technical mitigation potential. So technically not the same options to reduce their emissions,
    2. but also that the cost of these different options in the different sectors is different.

And on the two graphs at the bottom, you can see the amount of the emissions reductions by sector in the 2-degree scenario compared to the reference scenario. And I’m just showing you one example here.

But I want to stress what is really a general result of all global mitigation scenarios that limit the rise in temperature below 2-degree Celsius and it is that emissions from the power generation are reduced frankly to almost zero in these scenarios. And electricity production by 2050 is almost completely decarbonized and because power generation is done by using zero or very low sources of energy such as renewable energy, hydro, solar, wind, geothermal, that’s renewable energies. Or on the other hand, nuclear power or fossil fuel plus carbon capture and sequestration. This is a very important result, because the power generation in 2-degree Celsius scenarios goes from being the major source of CO2 energy emissions today to being almost completely decarbonized. So producing virtually zero CO2 energy emissions by 2050.

Another result going beyond power generation is of course that the emission reductions in the other sectors, so in building, industry and transport are also very substantial. So I don’t want to pretend like this is only an agenda for the power sector. This is certainly not the case. The power sector needs to be at the front and center of the deep Decarbonization of energy system, that is for sure, but the energy end use sectors also need to see their emissions decreasing very significantly and very quickly. For example, in the order of 40% for the transport sector in 2050 and 70% for the industry and building sectors in this scenario.543
There are two things I would like to say to conclude this lecture.

The first is that this global mitigation scenario as all the others, again, I picked one example, but all the conclusions can be applied to all the scenarios. This global mitigation scenario consistent with the 2-degree limit rests on the deployment of technologies that are not yet technologically mature, or that are still far too costly to achieve deep decarbonization. Examples of these technologies include carbon capture and sequestration, or nuclear force generation, or smart grids and energy storage to be able to operate the power system with high shares of intermittent. That is, intrinsically time variable renewable energy such as wind power or solar power. It is clear that these technologies will need further research, development and demonstration before they can be deployed at scale and at reasonable costs.

The second thing I want to mention is that I presented you the results of a global mitigation scenario. But as we’re going to see, country specific deep decarbonization strategies show a very wide variety of different approaches based on different national circumstances. These different circumstances includes things like different socioeconomic conditions or different natural resources endowments such as, well different availability of renewable energy potential, or different potential for carbon sequestration sites, or also, and it’s very important to take that into account, different national preferences regarding the different technologies, nuclear or CCS or other technologies. But in the next lectures we will look in further detail at these two questions.

  • First, the key technological challenges that must be met to achieve deep Decarbonization and we will discuss each of them in detail,
  • and second, we will be looking at country-specific case studies to see really concretely how deep decarbonization can be achieved within very different national contexts.

The Deep Decarbonization of Energy Systems III

The 3 Pillars of the Deep Decarbonization of Energy Systems

Welcome to chapter three of lecture five. I kept you waiting and I’m really sorry for that, but now is the time to start to looking at the solutions to the challenge of the deep decarbonization of our energy systems. How can we do it, that is the question? And in particular, how can we do it while making sure that we satisfy the conditions for continued economic growth and development and making sure that there is growing prosperity over the globe. This is precisely what we’re going to discuss in this chapter.

531But first let me recap what is the scale of the challenge. As we discussed previously, CO2 energy related emissions are of approximately 32 gigaton today, gigaton or billion tons. To have a likely chance which let me remind you, we defined as a probability higher than two-thirds, higher than 66%, to have a likely chance then of staying within the 2-degree limit, the need to get down to approximately 11 gigaton by 2050.

By comparison, to have a 50% chance only, so only one of out two of keeping below the 2-degree limit, the need to reach approximately 15 gigaton by 2050. So we’re roughly talking of a division by a factor two or even three of CO2 energy emissions in the next 40 years.

When in the meantime the world population is expected to grow and it is expected to grow by approximately one-third by 2050 compared to today.

532And the world GDP is also expected to grow and much faster in fact than the world population. It is expected to be multiplied by something like three by 2050 compared to today. So if we combine these different numbers together it means that we’re talking of dividing emissions per capita by something in between two-thirds and three-fourths by mid-century. And dividing emissions per GDP by a factor of six or nine by 2050, which is huge.

And so how can we achieve this decoupling between population and GDP growth on the one hand and energy consumption and CO2 emissions on the other hand?

If you’ve looked at the number, this is by any standard a major challenge, but this is certainly feasible. And I want to show you how.533

The easiest way to understand how that can be done is to decompose the drivers of CO2 emissions. CO2 emissions can be expressed as the product of four inputs. CO2 emissions equal population, that is the first term multiplied by GDP per capita, that is the second term, multiplied by energy use per unit of GDP, that is the third term, multiplied by the CO2 emissions per unit of energy, that is the fourth term. If you multiply these four terms, you get simply the CO2 emissions.

I’m just decomposing CO2 emissions into these four terms to explain you where the emissions come from and in turn, to explain you how the emissions can be reduced, through which mechanisms in particular.

If we take as a given the population trajectory and if we assume a rising trajectory of GDP per capita, in line with successful economic growth and, and development, then the CO2 emissions are driven mainly by the two last factors out of the four.

The first is the energy divided by GDP. And the second are the CO2 emissions divided by energy.

The first term is what we call the energy intensity, meaning very simply the amount of energy per unit of final output. The amount of energy we consume per unit of GDP we produce. The second term is the carbon intensity of energy, meaning the, the amount of carbon emissions per unit of energy we consume.

So let’s look at the ways in which we can reduce these two different ratios?

534So first, the energy intensity of GDP or as I said very simply, the energy consumption divided by GDP. It can be reduced through what we call energy efficiency and energy conservation measures in all the energy end use sectors. And we’re going to look in detail at each of them. First, passenger transportation and freight transport. Second, residential and commercial buildings. And third, industry.

So what’s the difference in between energy efficiency and energy conservation?

Because I just used both. Well usually we call

  • energy efficiency the technical improvements of products and processes. And we use the term,
  • energy conservation to describe a broader set of measures, including not only technical improvements, but more profoundly structural and behavioral changes that lead to lower levels of energy consumed per unit of GDP.

So let’s simply look at some examples to be very concrete and very precise. Examples of energy efficiency and energy conservation measures in the passenger transport and freight transport, for example to start with.535

  • Well first, improved vehicle technologies. That is more efficient vehicles. Vehicles using less gasoline for example per kilometer traveled.
  • Second, what we can call smart urban design. You can think at least of two things. One, building public transportation systems to reduce the need for the use of private cars, but you can think even more profoundly about building cities in a way that minimizes the distance to travel from where we live to where we work. Again, reducing the need for private transportation cars.
  • Third example. Optimized value change. Again, to minimize the distance, but this time the distance we need to ship the products from where they are produced to where they are consumed.

If we look at the residential and the commercial building sector, we can also think of a number of different options.

  • First, improved end use equipment. So more energy efficient equipment in our 536buildings.
  • But also what we could call smart architectural design. So building our houses in a way that reduces the need for cooling or heating for example.
  • More generally, improved building practices to improve the energy efficiency of the building envelope and also the use of different, less energy intensive construction materials.

If we look at the industry sector, again, many different options for an energy efficiency such

  • as improved equipment and production processes,
  • material efficiency, but also very importantly because the industry is a huge consumer of heat to produce its products.
  • So reuse of waste heat is an important part of the energy efficiency measures in industry.

So that’s it for all the different ways in he different sectors in which we can improve the energy efficiency of GDP.

So the ratio of energy consumption divided by GDP. But as I said, it’s not the only driver of possible emission reductions.

We now need to looked at the other term, the improvement in the carbon intensity of energy or the ratio of CO2 emissions per unit of energy consumed. And here too the carbon intensity of energy can be reduced in two different ways.

The first is and very importantly, because it’s really at the core of any successful deep decarbonization strategy, it is the decarbonization of electricity generation. So as I said, your objective is the replacement of the uncontrolled fossil fuels, the phase out of the uncontrolled fossil fuels to produce electricity by a mix of different options, because there are different options to produce electricity with no or very little CO2 emissions.

The first is a mix of all different sorts of renewable energy such as hydropower, wind power, solar power, or geothermal energy. But you can also think of using nuclear power or using the fossil fuels, so the coal and the gas used to produce electricity, but with carbon capture and sequestration. So that’s a first important way in which we can decrease the carbon intensity of energy, by decarbonizing the way we produce electricity.

There is another way which we call fuel switching. It means switching end use energy supplies from highly carbon intensive fossil fuels in transportation or in buildings and in the industry to lower carbon fuels. Electricity is of course one of these possible lower carbon fuels, provided it is decarbonized. But there are other possible forms of lower carbon fuels and in particular, the use of biofuels. So again, this is another way of reducing the carbon intensity of energy which we call fuel switching, switching fuel from high carbon to low carbon sources of energy. So let me summarize.537

The deep Decarbonization of energy systems rests on three pillars.

  • The first is energy efficiency and conservation measures.
  • The second is the production of low carbon electricity.
  • And the third is the switching of fuels from high to low carbon energy carriers.

I want to stress here that electricity plays a pivotal role in the deep Decarbonization scenarios because you see electricity in two out of the three pillars.

  • First you see that electricity needs to be almost completely decarbonized and we’re going to come back to that in a moment.
  • But also because electricity overall plays a more important role in energy consumption as fuel consumption switches from high carbon to low carbon options.

It is very important that you remember these three pillars because they really represent the basic framework to think about the deep decarbonization of energy systems in any circumstance. As we’re going to see in the next lectures, the precise options within each of these three pillars, but also their relative importance is going to vary of course from one country to the next. But these three pillars really represent the basic foundation to think about deep decarbonization.

The Deep Decarbonization of Energy Systems IV

Global Mitigation Scenario

In the previous chapter, I introduced the three pillars of the deep decarbonization of our energy system. So let me just very quickly recap what they are.

  • First, the energy efficiency and conservation measures.
  • Second, the production of low carbon electricity.
  • And third the fuel switching from high carbon to low carbon energy carriers.

537As I said, these three pillars represent the overarching framework for these deep decarbonization strategies of our energy system. But before we conclude this lecture, there are still two questions that we need to answer.

  • The first is how do these pillars apply to the different sectors of the economy and how can the coordinated implementation of these three strategies result in the overall deep Decarbonization of the economy?
  • The second question is very importantly, the quantification of their effect by how much do each sector emissions need to be reduced to reach level of deep decarbonization consistent with the objective of limiting the increase in mean surface temperature below 2-degree Celsius?

To answer these two questions we’re going to use the results of a global modeling scenario. The graph in the top left corner represents the business-as-usual scenario, or the continuation of the current trends. This is if you will, the scenario if we don’t implement climate change mitigation policies which by the way, means that this is a scenario in which we don’t avoid dangerous climate change and we would face the catastrophic consequences from an uncontrolled climate change. As you can see on this graph, on the top left corner, CO2 energy emissions are increasing sharply. They go from approximately 35 gigaton of CO2 energy emissions by 2015 to more than 50 gigaton of CO2 energy by 2050. And in this scenario, in this business-as-usual scenario, emissions from all sectors are rising, but in particular, the emissions from power generation.541

To the country the graph in the top right-hand corner represents a 2-degree Celsius scenario. So in, in this scenario the CO2 emissions are reduced over time to a level that is consistent with the objective of staying within 2-degree of global warming. And as you can see on this graph, on the top right-hand corner emissions peak by approximately 2020 and then they’re reduced, they’re in fact reduced dramatically to approximately 11 gigaton of CO2 energy by 2050. So what do we really learn from the results of this global mitigation scenario? Well it shows a few important things.

  1. First it shows that staying within the 2-degree limit requires deep emission reductions in all sectors of the economy. Profound emission reductions in power generation, industry, transport and buildings. But what is interesting is that it shows also that these sectoral emissions, the emissions from the different sectors are reduced in different proportions. And that is due mainly to two factors.
    1. I mean first, the fact that the different sectors do not have the same technical mitigation potential. So technically not the same options to reduce their emissions,
    2. but also that the cost of these different options in the different sectors is different.

And on the two graphs at the bottom, you can see the amount of the emissions reductions by sector in the 2-degree scenario compared to the reference scenario. And I’m just showing you one example here.

542But I want to stress what is really a general result of all global mitigation scenarios that limit the rise in temperature below 2-degree Celsius and it is that emissions from the power generation are reduced frankly to almost zero in these scenarios. And electricity production by 2050 is almost completely decarbonized and because power generation is done by using zero or very low sources of energy such as renewable energy, hydro, solar, wind, geothermal, that’s renewable energies. Or on the other hand, nuclear power or fossil fuel plus carbon capture and sequestration. This is a very important result, because the power generation in 2-degree Celsius scenarios goes from being the major source of CO2 energy emissions today to being almost completely decarbonized. So producing virtually zero CO2 energy emissions by 2050.

  1. Another result going beyond power generation is of course that the emission reductions in the other sectors, so in building, industry and transport are also very substantial. So I don’t want to pretend like this is only an agenda for the power sector. This is certainly not the case. The power sector needs to be at the front and center of the deep Decarbonization of energy system, that is for sure, but the energy end use sectors also need to see their emissions decreasing very significantly and very quickly. For example, in the order of 40% for the transport sector in 2050 and 70% for the industry and building sectors in this scenario.

There are two things I would like to say to conclude this lecture.

The first is that this global mitigation scenario as all the others, again, I picked one example, but all the conclusions can be applied to all the scenarios. This global mitigation scenario consistent with the 2-degree limit rests on the deployment of technologies that are not yet technologically mature, or that are still far too costly to achieve deep decarbonization. Examples of these technologies include carbon capture and sequestration, or nuclear force generation, or smart grids and energy storage to be able to operate the power system with high shares of intermittent. That is, intrinsically time variable renewable energy such as wind power or solar power. It is clear that these technologies will need further research, development and demonstration before they can be deployed at scale and at reasonable costs.

The second thing I want to mention is that I presented you the results of a global mitigation scenario. But as we’re going to see, country specific deep decarbonization strategies show a very wide variety of different approaches based on different national circumstances.

543These different circumstances includes things like different socioeconomic conditions or different natural resources endowments such as, well different availability of renewable energy potential, or different potential for carbon sequestration sites, or also, and it’s very important to take that into account, different national preferences regarding the different technologies, nuclear or CCS or other technologies. But in the next lectures we will look in further detail at these two questions.

  • First, the key technological challenges that must be met to achieve deep Decarbonization and we will discuss each of them in detail,
  • and second, we will be looking at country-specific case studies to see really concretely how deep decarbonization can be achieved within very different national contexts.

The Deep Decarbonization of Energy Systems III

The 3 Pillars of the Deep Decarbonization of Energy Systems

Welcome to chapter three of lecture five. I kept you waiting and I’m really sorry for that, but now is the time to start to looking at the solutions to the challenge of the deep decarbonization of our energy systems. How can we do it, that is the question? And in particular, how can we do it while making sure that we satisfy the conditions for continued economic growth and development and making sure that there is growing prosperity over the globe. This is precisely what we’re going to discuss in this chapter.

But first let me recap what is the scale of the challenge. As we discussed previously, CO2 energy related emissions are of approximately 32 gigaton today, gigaton or billion tons. To have a likely chance which let me remind you, we defined as a probability higher than two-thirds, higher than 66%, to have a likely chance then of staying within the 2-degree limit, the need to get down to approximately 11 gigaton by 2050.531

By comparison, to have a 50% chance only, so only one of out two of keeping below the 2-degree limit, the need to reach approximately 15 gigaton by 2050. So we’re roughly talking of a division by a factor two or even three of CO2 energy emissions in the next 40 years.

When in the meantime the world population is expected to grow and it is expected to grow by approximately one-third by 2050 compared to today.532

And the world GDP is also expected to grow and much faster in fact than the world population. It is expected to be multiplied by something like three by 2050 compared to today. So if we combine these different numbers together it means that we’re talking of dividing emissions per capita by something in between two-thirds and three-fourths by mid-century. And dividing emissions per GDP by a factor of six or nine by 2050, which is huge.

And so how can we achieve this decoupling between population and GDP growth on the one hand and energy consumption and CO2 emissions on the other hand?

If you’ve looked at the number, this is by any standard a major challenge, but this is certainly feasible. And I want to show you how.

The easiest way to understand how that can be done is to decompose the drivers of CO2 emissions. CO2 emissions can be expressed as the product of four inputs. CO2 emissions equal population, that is the first term multiplied by GDP per capita, that is the second term, multiplied by energy use per unit of GDP, that is the third term, multiplied by the CO2 emissions per unit of energy, that is the fourth term. If you multiply these four terms, you get simply the CO2 emissions.

I’m just decomposing CO2 emissions into these four terms to explain you where the emissions come from and in turn, to explain you how the emissions can be reduced, through which mechanisms in particular.533

If we take as a given the population trajectory and if we assume a rising trajectory of GDP per capita, in line with successful economic growth and, and development, then the CO2 emissions are driven mainly by the two last factors out of the four.

The first is the energy divided by GDP. And the second are the CO2 emissions divided by energy.

The first term is what we call the energy intensity, meaning very simply the amount of energy per unit of final output. The amount of energy we consume per unit of GDP we produce. The second term is the carbon intensity of energy, meaning the, the amount of carbon emissions per unit of energy we consume.

So let’s look at the ways in which we can reduce these two different ratios?534

So first, the energy intensity of GDP or as I said very simply, the energy consumption divided by GDP. It can be reduced through what we call energy efficiency and energy conservation measures in all the energy end use sectors. And we’re going to look in detail at each of them. First, passenger transportation and freight transport. Second, residential and commercial buildings. And third, industry.

So what’s the difference in between energy efficiency and energy conservation?

Because I just used both. Well usually we call

  • energy efficiency the technical improvements of products and processes. And we use the term,
  • energy conservation to describe a broader set of measures, including not only technical improvements, but more profoundly structural and behavioral changes that lead to lower levels of energy consumed per unit of GDP.

So let’s simply look at some examples to be very concrete and very precise. Examples of energy efficiency and energy conservation measures in the passenger transport and freight transport, for example to start with.535

  • Well first, improved vehicle technologies. That is more efficient vehicles. Vehicles using less gasoline for example per kilometer traveled.
  • Second, what we can call smart urban design. You can think at least of two things. One, building public transportation systems to reduce the need for the use of private cars, but you can think even more profoundly about building cities in a way that minimizes the distance to travel from where we live to where we work. Again, reducing the need for private transportation cars.
  • Third example. Optimized value change. Again, to minimize the distance, but this time the distance we need to ship the products from where they are produced to where they are consumed.

If we look at the residential and the commercial building sector, we can also think of a number of different options.

  • First, improved end use equipment. So more energy efficient equipment in our buildings.
  • But also what we could call smart architectural design. So building our houses in a way that reduces the need for cooling or heating for example.
  • More generally, improved building practices to improve the energy efficiency of the building envelope and also the use of different, less energy intensive construction materials.

If we look at the industry sector, again, many different options for an energy efficiency such

  • as improved equipment and production processes,
  • material efficiency, but also very importantly because the industry is a huge consumer of heat to produce its products.
  • So reuse of waste heat is an important part of the energy efficiency measures in industry.

536So that’s it for all the different ways in he different sectors in which we can improve the energy efficiency of GDP.

So the ratio of energy consumption divided by GDP. But as I said, it’s not the only driver of possible emission reductions.

We now need to looked at the other term, the improvement in the carbon intensity of energy or the ratio of CO2 emissions per unit of energy consumed. And here too the carbon intensity of energy can be reduced in two different ways.

The first is and very importantly, because it’s really at the core of any successful deep decarbonization strategy, it is the decarbonization of electricity generation. So as I said, your objective is the replacement of the uncontrolled fossil fuels, the phase out of the uncontrolled fossil fuels to produce electricity by a mix of different options, because there are different options to produce electricity with no or very little CO2 emissions.

The first is a mix of all different sorts of renewable energy such as hydropower, wind power, solar power, or geothermal energy. But you can also think of using nuclear power or using the fossil fuels, so the coal and the gas used to produce electricity, but with carbon capture and sequestration. So that’s a first important way in which we can decrease the carbon intensity of energy, by decarbonizing the way we produce electricity.

There is another way which we call fuel switching. It means switching end use energy supplies from highly carbon intensive fossil fuels in transportation or in buildings and in the industry to lower carbon fuels. Electricity is of course one of these possible lower carbon fuels, provided it is decarbonized. But there are other possible forms of lower carbon fuels and in particular, the use of biofuels. So again, this is another way of reducing the carbon intensity of energy which we call fuel switching, switching fuel from high carbon to low carbon sources of energy. So let me summarize.

The deep Decarbonization of energy systems rests on three pillars.

  • The first is energy efficiency and conservation measures.
  • The second is the production of low carbon electricity.
  • And the third is the switching of fuels from high to low carbon energy carriers.

I want to stress here that electricity plays a pivotal role in the deep Decarbonization scenarios because you see electricity in two out of the three pillars.

  • First you see that electricity needs to be almost completely decarbonized and we’re going to come back to that in a moment.
  • But also because electricity overall plays a more important role in energy consumption as fuel consumption switches from high carbon to low carbon options.

It is very important that you remember these three pillars because they really represent the basic framework to think about the deep decarbonization of energy systems in any circumstance. As we’re going to see in the next lectures, the precise options within each of these three pillars, but also their relative importance is going to vary of course from one country to the next. But these three pillars really represent the basic foundation to think about deep decarbonization.

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